*Description*: A schematic diagram of velocity measurements of a rotating disk of hot gas in the core of active galaxy M87. The measurement was made by studying how the light from the disk is redshifted and blueshifted _Ôø___Ôø__ as part of the swirling disk spins in earth's direction and the other side spins away from earth. The gas on one side of the disk is speeding away from Earth, at a speed of about 1.2 million miles per hour (550 kilometers per second). The gas on the other side of the disk is orbiting around at the same speed, but in the opposite direction, as it approaches viewers on Earth. This high velocity is the signature of the tremendous gravitational field at the center of M87. This is clear evidence that the region harbors a massive black hole, since it contains only a fraction of the number of stars that would be necessary to create such a powerful attraction. A black hole is an object that is so massive yet compact nothing can escape its gravitational pull, not even light. The object at the center of M87 fits that description. It weights as much as three billion suns, but is concentrated into a space no larger than our solar system. The observations were made with HST's Faint Object Spectrograph. Technical facts about this news release: Back to entire collection [ http://hubblesite.org/newscenter/archive/releases/index/562/ ] Next release [ http://hubblesite.org/newscenter/archive/releases/1994/20/ ] Previous release [ http://hubblesite.org/newscenter/archive/releases/1994/24/ ] *News Release Number:*: STScI-1994-23b

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